title: Maternal influence on child HPA axis: a prospective study of cortisol levels in hair.
abstract: OBJECTIVE
  To investigate cortisol concentrations in hair as biomarker of prolonged stress in young children and their mothers and the relation to perinatal and sociodemographic factors.
  
  
  METHODS
  Prospective cohort study of 100 All Babies In Southeast Sweden study participants with repeated measures at 1, 3, 5, and 8 years and their mothers during pregnancy. Prolonged stress levels were assessed through cortisol in hair. A questionnaire covered perinatal and sociodemographic factors during the child's first year of life.
  
  
  RESULTS
  Maternal hair cortisol during the second and third trimester and child hair cortisol at year 1 and 3 correlated. Child cortisol in hair levels decreased over time and correlated to each succeeding age, between years 1 and 3 (r = 0.30, P = .002), 3 and 5 (r = 0.39, P < .001), and 5 and 8 (r = 0.44, P < .001). Repeated measures gave a significant linear association over time (P < .001). There was an association between high levels of hair cortisol and birth weight (β = .224, P = .020), nonappropriate size for gestational age (β = .231, P = .017), and living in an apartment compared with a house (β = .200, P = .049). In addition, we found high levels of cortisol in hair related to other factors associated with psychosocial stress exposure.
  
  
  CONCLUSIONS
  Correlation between hair cortisol levels in mothers and their children suggests a heritable trait or maternal calibration of the child's hypothalamic-pituitary-adrenocortical axis. Cortisol output gradually stabilizes and seems to have a stable trait. Cortisol concentration in hair has the potential to become a biomarker of prolonged stress, especially applicable as a noninvasive method when studying how stress influences children's health.
authors.affiliation: Division of Community Medicine, Department of Medicine and Health Sciences, Linköping University, SE-581 83 Linköping, Sweden. jerker.karlen@liu.se.
authors.forename: Jerker
authors.initials: J
authors.lastname: Karlén
authors.forename: Anneli
authors.initials: A
authors.lastname: Frostell
authors.forename: Elvar
authors.initials: E
authors.lastname: Theodorsson
authors.forename: Tomas
authors.initials: T
authors.lastname: Faresjö
authors.forename: Johnny
authors.initials: J
authors.lastname: Ludvigsson
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006197:Hair / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007223:Infant; D008297:Male; D008429:Maternal Welfare / Q000523:psychology*; D009034:Mother-Child Relations / Q000523:psychology*; D010913:Pituitary-Adrenal System / Q000378:metabolism; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000378:metabolism; D011446:Prospective Studies; D013315:Stress, Psychological / Q000453:epidemiology / Q000378:metabolism* / Q000523:psychology*; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone
keywords: children; cortisol; hair; health disparities; mother; stress